<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>jQuery</title>
</head>
<body>
    <p>文字1</p>
    <p>文字2</p>
    <p>文字3</p>
    
    

    <script src='./demo.js'></script>
    
</body>
</html>